【作者】 曹源；

【导师】 孙辉； 刘伟；

【作者基本信息】 四川大学 ， 环境工程（专业学位）， 2023， 硕士

【摘要】 各种人为活动造成的土壤镉(Cd)污染是一个普遍的环境问题,农田土壤的Cd污染已对食品安全和人类健康构成严重威胁。我国农田土壤中Cd的污染范围较广,大规模修复的成本较高昂,因此基于低重金属累积经济作物筛选的安全利用是当前前景较好的解决方案。我国中药材资源丰富,尤其是四川。但近年来关于中药材Cd含量超标的现象时有报道,严重威胁中药产业的可持续发展。目前中药材低重金属累积品种筛选的研究较少,中药材在Cd污染农田土壤的安全利用潜力有待挖掘。本研究以药用部位分别为块根(())、)叶和花果的6种中药材为研究对象,探究其在全生长周期的Cd吸收转移特征,并分析了Cd在亚细胞水平的螯合固定特征和Cd与其他矿质元素的相关性;探究了其药用部位主要有效成分的变化规律,以及体外抗氧化能力;最后,基于层次分析法、CRITIC-TOPSIS(CRiteria Importance Through Intercriteria CorrelationTechnique for Order Preference by Similarity to an Ideal Solution)评价法和熵权-灰色综合评价法三种评价方法、选用11项指标对研究对象进行Cd污染土壤安全利用潜力的综合评价,主要研究结果如下:(1)Cd更易累积在中药材的根系,并在休眠期向地上部分转移,块根(())和果实不易累积。根据药典标准药用部位Cd含量低于1 mg/kg标准,天冬(ASPARAGI RADIX)(Cd含量0.53～0.77 mg/kg)和紫苏梗(PERILLAE CAULIS)(Cd含量0.08～0.84 mg/kg)的安全采收期最长,7—10月均达标;菊花(CHRYSANTHEMI FLOS)(Cd含量2.07～8.38 mg/kg)最差,7—10月均不达标;其他中药材均为部分月份达标。(2)在中药材各部位细胞中,Cd主要分布在细胞壁和液泡中,细胞器组分Cd占比最少。随着植株生长,只有白芨(BLETILLAE RHIZOMA)根系细胞器Cd占比增加,说明白芨根系细胞受到Cd毒害作用可能较大。(3)Cd与其他矿质元素的相关性在种间和种内不同部位间存在差异。综合来看,Cd与Fe、Mn、Al、Si和Na呈负相关关系,与Zn、Cu、Ca、Mg和K呈正向相关关系。通过文献调研,在本研究中,Cd可能影响了中药材植株的光合作用、金属转运蛋白和通道蛋白的表达、细胞内外渗透压平衡和抗重金属胁迫防御系统的构筑。(4)中药材各月份的主要有效成分含量和体外抗氧化能力有所差异。中药材白芨和天冬的总酚含量分别在9月、10月最高且自由基的清除效果也最好;薄荷((MENTHAE HAPLOCALYCIS HERBA)、紫苏叶(PERILLAE FOLIUM)和紫苏梗的有效成分含量分别在8月、7月和9月最高;菊花在7月各有效成分含量最高,自由基的清除效果也最好,决明子(CASSIAE SEMEN)在每月的有效成分相对稳定,且在10月对自由基清除效果最好。(5)不同综合评价方法得到的结果不同,在评价方法的选择上应根据实际。其中层次分析法侧重安全性;TOPSIS评价法侧重经济性;灰色综合评价法侧重药用价值。本研究重点考虑中药材安全利用的安全性,因此层次分析法结果更有参考意义。依据层次分析法结果,兼顾中药材品种及采收月份,得到以下安全利用优先顺序:薄荷7月、紫苏梗9月、紫苏梗7月、紫苏叶7月、紫苏梗8月、白芨10月、天冬8月和决明子9月。更多还原

【Abstract】 Soil cadmium(Cd)pollution caused by various human activities is a common environmental problem.Cd pollution in farmland soil has posed a serious threat to food safety and human health.The range of Cd pollution in agricultural soil is extensive in China,and large-scale remediation has been prohibitively expensive.Therefore,safe utilization based on screening of cash crops with low heavy metal accumulation is a promising solution at present.China has abundant resources of traditional Chinese medicinal materials,especially in Sichuan Province.However,in recent years,the excessive Cd content in traditional Chinese medicinal materials has been reported,which affects the sustainable development of the traditional Chinese medicine industry.Currently,there have been few studies on the screening of low heavy metal accumulation varieties of traditional Chinese medicinal materials,and the potential for safe utilization of traditional Chinese medicinal materials in Cdpolluted agricultural soil needs to be explored.In this study,the absorption and transfer characteristics of Cd in the whole growth cycle of six kinds of traditional Chinese medicine materials with medicinal parts as tuber and rhizome,stem and leaf,flower and fruit were investigated,and the chelation and fixation characteristics of Cd at subcellular level and the correlation between Cd and other mineral elements were analyzed.Furthermore,the change rules of the main active components of the medicinal parts and the antioxidant capacity in vitro were explored.Finally,we have evaluated the potential for safe utilization of the research objects in Cd-contaminated soil based on three comprehensive evaluation methods: analytic hierarchy process,CRITIC-TOPSIS evaluation method,and entropy weight-grey correlation comprehensive evaluation method,with 11 indicators.The main research results have been as follows:(1)Cd has been found to accumulate more easily in the roots of traditional Chinese medicinal materials,and transfer to the above-ground parts during the dormant period,with lower accumulation in rhizomes and fruit.According to the pharmacopoeia standard,the Cd content in the medicinal parts should be below 1mg/kg.The safe harvesting period for ASPARAGI RADIX(天冬)(Cd content0.53～0.77 mg/kg)and PERILLAE CAULIS(紫苏梗)(Cd content 0.08～0.84 mg/kg)was the longest,which reached the standard from July to October.While that of CHRYSANTHEMI FLOS(菊花)(Cd content 2.07～8.38 mg/kg)was the worst,which was not up to the standard from July to October.Other traditional Chinese medicinal materials reached the standards for some months.(2)In cells of various parts of traditional Chinese medicinal materials,Cd was mainly distributed in the cell wall and vacuole,and the proportion of organelle component Cd was the least.As the plants grew,only the proportion of Cd in root organelles of BLETILLAE RHIZOMA(白芨)increased,indicating that the root cell of BLETILLAE RHIZOMA may be more affected by Cd toxicity.(3)The correlation of Cd with other mineral elements varied between species and between different parts of the species.Overall,Cd was negatively correlated with Fe,Mn,Al,Si,and Na,and positively correlated with Zn,Cu,Ca,Mg,and K.Through literature research,in this study,Cd may have affected plant photosynthesis,expression of other metal transporters and channel proteins,intracellular and extracellular osmotic balance,and the construction of defense systems against heavy metal stress.(4)The content of the main active ingredients and the in vitro antioxidant capacity of traditional Chinese medicinal materials varied from month to month.The total phenolic content of BLETILLAE RHIZOMA and ASPARAGI RADIX were highest in September and October respectively,and the free radical scavenging effects were also the best.The effective ingredient content of MENTHAE HAPLOCALYCIS HERBA(薄荷),PERILLAE FOLIUM(紫苏叶)and PERILLAE CAULIS was highest in August and September,respectively.The effective ingredient content of CHRYSANTHEMI FLOS was highest in September,but its free radical scavenging effect was the best in July.The effective ingredient content of CASSIAE SEMEN(决明子)was relatively stable each month,and its free radical scavenging effect was the best in October.(5)The results obtained from different comprehensive evaluation methods vary.The selection of evaluation methods should be based on actual needs.The Analytic Hierarchy Process(AHP)focuses on safety;the Technique for Order of Preference by Similarity to Ideal Solution(TOPSIS)focuses on economy;and the Grey Comprehensive Evaluation(GCE)method focuses on medicinal value.In this study,we focused on the safety of the safe use of traditional Chinese medicinal materials,and therefore the results of the AHP are more meaningful.Based on the results of the analytic hierarchy process,taking into account the varieties of traditional Chinese medicine and the harvest month,the following safety utilization priorities were obtained: MENTHAE HAPLOCALYCIS HERBA in July,PERILLAE CAULIS in September,PERILLAE CAULIS in July,PERILLAE FOLIUM in July,PERILLAE CAULIS in August,BLETILLAE RHIZOMA in October,ASPARAGI RADIX in August and CASSIAE SEMEN in September.更多还原